Xen Hypervisor Translated Guest Self-linear Shadow Mapping Handling Guest-to-Host Privilege Escalation (XSA-243)

#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(103978);
  script_version("1.7");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id(
    "CVE-2017-15588",
    "CVE-2017-15589",
    "CVE-2017-15590",
    "CVE-2017-15591",
    "CVE-2017-15592",
    "CVE-2017-15593",
    "CVE-2017-15594",
    "CVE-2017-15595",
    "CVE-2017-15596"
  );
  script_bugtraq_id(101490, 101496, 101500);
  script_xref(name:"IAVB", value:"2017-B-0142-S");

  script_name(english:"Xen Hypervisor Translated Guest Self-linear Shadow Mapping Handling Guest-to-Host Privilege Escalation (XSA-243)");
  script_summary(english:"Checks 'xl info' output for the Xen hypervisor version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote Xen hypervisor installation is missing a security update.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version number, the Xen hypervisor
installed on the remote host is affected by an unspecified flaw in
mm/shadow/multi.c that is triggered during the handling of self-linear
shadow mappings with translated guests. This may allow an attacker on
the guest to cause a denial of service or gain  elevated privileges on
the host.

Note that Nessus has checked the changeset versions based on the
xen.git change log. Nessus did not check guest hardware configurations
or if patches were applied manually to the source code before a
recompile and reinstall.");
  script_set_attribute(attribute:"see_also", value:"http://xenbits.xen.org/xsa/advisory-243.html");
  script_set_attribute(attribute:"see_also", value:"https://xenbits.xen.org/gitweb/?p=xen.git;a=summary");
  script_set_attribute(attribute:"solution", value:
"Apply the appropriate patch according to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-15595");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/10/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/10/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/10/19");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:xen:xen");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2017-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("xen_server_detect.nbin");
  script_require_keys("installed_sw/Xen Hypervisor", "Settings/ParanoidReport");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("install_func.inc");
include("misc_func.inc");

app_name = "Xen Hypervisor";
install  = get_single_install(app_name:app_name);
if (report_paranoia < 2) audit(AUDIT_PARANOID);

version         = install['version'];
display_version = install['display_version'];
path            = install['path'];
managed_status  = install['Managed status'];
changeset       = install['Changeset'];

if (!empty_or_null(changeset))
  display_version += " (changeset " + changeset + ")";

# Installations that are vendor-managed are handled by OS-specific local package checks
if (managed_status == "managed")
  audit(AUDIT_INST_PATH_NOT_VULN, app_name, display_version, path);

# XSA-243
fixes['4.5']['fixed_ver']           = '4.5.5';
fixes['4.5']['fixed_ver_display']   = '4.5.5 (changeset bbeb763)';
fixes['4.5']['affected_ver_regex']  = '^4\\.5\\.';
fixes['4.5']['affected_changesets'] = make_list("5fdf16f", "0e9967d",
  "da4f24d", "b7582ac", "196371c", "7afc8ad", "72c107b", "5659aa5",
  "a224de6", "6442fa9", "db487a6", "709230f", "83724d9", "04b8c4c",
  "0b2ceae", "e3f0768", "d5a5231", "c5b0fe5", "136ff4e", "42c8ba5",
  "d38489d", "df59014", "3217129", "4964e86", "c079597", "6ec173b",
  "a373456", "0780e81", "e5ef76d", "25eaa86", "ae02360", "5597df9",
  "c5de05e", "773094e", "e39a248", "7b3712a", "be35327", "8825df1",
  "d7e3725", "6eb61e4", "b1fcfed", "5779d6a", "afdd77e", "c18367a",
  "7b7fd80", "b30e165", "62ef9b2", "8071724", "235b5d5", "a28b99d",
  "ff294fc", "bc01e2d", "da50922", "386cc94", "139960f", "ec3ddd6",
  "988929a", "1c48dff", "20d4248", "9610422", "cd76cd3", "455fd66",
  "b820c31", "ac3d8bc", "cde86fc", "1678521", "83cb2db", "43d06ef",
  "2b17bf4", "1a2bda5", "0bd7faf", "e3426e2", "37281bc", "27be856",
  "bdf3ef1", "cc325c0", "8e7b84d", "387b8ae", "34fbae7", "1530da2",
  "274a1f6", "b679cfa", "877b760", "cfe165d", "84e4e56", "e4ae4b0");

fixes['4.6']['fixed_ver']           = '4.6.6';
fixes['4.6']['fixed_ver_display']   = '4.6.6 (changeset d8b0ebf)';
fixes['4.6']['affected_ver_regex']  = '^4\\.6\\.';
fixes['4.6']['affected_changesets'] = make_list("f0208a4", "42b2c82",
  "57318e1", "9f22d72", "e0353b4", "76f1549", "9bac910", "c7a43e3",
  "913d4f8", "c5881c5", "b0239cd", "78fd0c3", "9079e0d", "1658a87",
  "22b6dfa", "a8cd231", "629eddd", "64c03bb", "b4660b4", "1ac8162",
  "747df3c", "5ae011e", "f974d32", "3300ad3", "d708b69");

fixes['4.7']['fixed_ver']           = '4.7.4';
fixes['4.7']['fixed_ver_display']   = '4.7.4-pre (changeset 8cd1258)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("1d01ddc", "5ca7d11",
  "ebd47d4", "6a6a339", "e61be54", "e3f7a64", "957ad23", "b1ae705",
  "3add76f", "314a8fc", "d6aad63", "7c99633", "145c18d", "c3fa5cd",
  "487f8f9", "ffcfc40", "c7783d9", "3331050", "83966a3", "a67b223",
  "68dbba2", "2728470", "dea68ed", "9d12253", "73d7bc5", "b704b1a",
  "ca4ef7b", "ece330a", "3d63ebc", "30d50f8", "2dc3cdb", "5151257",
  "c9f3ca0", "e873251", "8aebf85", "c362cde", "fece08a");

fixes['4.8']['fixed_ver']           = '4.8.3';
fixes['4.8']['fixed_ver_display']   = '4.8.3-pre (changeset 96e6364)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("1a8ad09", "df89197",
  "c4f969d", "b1f3f1d", "7251c06", "1960ca8", "866cfa1", "ddd6e41",
  "370cc9a", "39e3024", "9f092f5", "667f70e", "2116fec", "1a535c3",
  "ee3fc24", "d623d82", "dda458c", "c642b12", "80d7ef3", "ff4f60a",
  "36898eb", "4d7ccae", "e574046", "90dafa4", "c020cf2");

fixes['4.9']['fixed_ver']           = '4.9.1';
fixes['4.9']['fixed_ver_display']   = '4.9.1-pre (changeset 7fe0a24)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("a2af47d", "61a2d31",
  "c2b0a92", "d842630", "ef61bcf", "44ceb19", "ae45442", "784afd9",
  "22032b2", "58da67f", "d1b64cc", "9cde7a8", "1cdcb36", "84c039e",
  "b244ac9", "612044a", "e8fd372", "a568e25", "8fef83e", "478e40c",
  "22ea731", "e7703a2", "91ded3b", "2cc3d32", "79775f5", "43cb0c4",
  "4821228", "d23bcc5", "308654c", "6fd84b3", "89b36cc", "a9ecd60",
  "798f6c9", "6508278", "5587d9a", "527fc5c", "5ff1de3", "692ed82",
  "9bf14bb", "c57b1f9", "6b147fd", "0e186e3", "afc5ebf", "266fc0e",
  "4698106", "f4f02f1", "0fada05", "ab4eb6c", "b29ecc7", "a11d14b",
  "107401e", "1b7834a");

fix = NULL;
foreach ver_branch (keys(fixes))
{
  if (version =~ fixes[ver_branch]['affected_ver_regex'])
  {
    ret = ver_compare(ver:version, fix:fixes[ver_branch]['fixed_ver']);
    if (ret < 0)
      fix = fixes[ver_branch]['fixed_ver_display'];
    else if (ret == 0)
    {
      if (empty_or_null(changeset))
        fix = fixes[ver_branch]['fixed_ver_display'];
      else
        foreach affected_changeset (fixes[ver_branch]['affected_changesets'])
          if (changeset == affected_changeset)
            fix = fixes[ver_branch]['fixed_ver_display'];
    }
  }
}

if (empty_or_null(fix))
  audit(AUDIT_INST_PATH_NOT_VULN, app_name, display_version, path);

items  = make_array("Installed version", display_version,
                    "Fixed version", fix,
                    "Path", path);
order  = make_list("Path", "Installed version", "Fixed version");
report = report_items_str(report_items:items, ordered_fields:order) + '\n';

security_report_v4(port:0, extra:report, severity:SECURITY_HOLE);